Successful breeding of Pets?

I have tried mating several times but with no luck. Last time I even got a note that my dog is pregnant and then one saying that she is in labour and finally I got to name two girl puppies but for some reason puppies haven't been borned no matter what notes have said. They don't show up in my househould. Maybe it's a bug?

//Now I noticed that one of my sims had the puppy in her relationships and once I called the puppy to come she showed up on the list of my sim family members on the bottom of a screen but I still can't find the other puppy.